1. Field of the Invention
The present invention relates to a color image processing apparatus, and more particularly to a color image processing apparatus capable of automatically discriminating whether the original image is a black-and-white original or a color original.
2. Related Background Art
The present applicant already proposed, for example in the U.S. patent applications Ser. No. 271,362 (now U.S. Pat. No. 4,953,012 issued Aug. 28, 1990) and Ser. No. 416,587, (now abandoned) a technology for use in a color copying apparatus, for automatically discriminating whether the original image is a black-and-white original or a color original, and executing black monochromic copying in case of a black-and-white original, or color copying with four colors of yellow, magenta, cyan and black in case of a color original. This technology allows to reduce the copying time and the copying cost.
However such conventional technology is incapable of exact discrimination for originals or areas of undefinite shape, because the discrimination is conducted over the entire area of the original.
Also in a structure in which the original image is pre-scanned prior to the image reading and the black monochromic copying or color copying is conducted according to the result of discrimination conducted on the output of said pre-scanning, the pre-scanning occupies a consideration portion of the operating time and deteriorates the efficiency of operation, particularly in case of handling plural original documents with an automatic document feeder, because the pre-scanning is conducted over the entire area of the original.
Also since the discrimination is conducted over the entire area of the original, in case of dividedly copying an original containing both a color image and a black-and-white image, reduction in the copying time or the copying cost cannot be achieved because a color process is conducted also on the black-and-white image.